Display shows “H0” or similar hardness error; water may feel hard even after regeneration.

Safety first: No internal electrical work is required for this step, but unplug the unit if you remove covers.

• Step 1 – Verify raw water hardness: Use a hardness test kit or contact your water supplier to confirm grains per gallon (gpg). Compare to the value programmed into the softener.
• Step 2 – Adjust settings: Increase the hardness setting by 10–20% if you have iron in the water or if hardness tests show breakthrough before regeneration.
• Step 3 – Check resin age: If the softener is more than 10–15 years old or has been exposed to iron without proper pre‑treatment, the resin may be fouled. Perform a resin cleaner treatment following the product instructions.
• Step 4 – Verify flow metering: Run water and confirm that the display shows flow and usage accumulating. If not, see turbine/flow sensor troubleshooting.
• Step 5 – Replace resin if needed: If hardness remains high despite correct settings and working flow sensor, replace the GE cation resin bed with compatible high‑capacity resin.